B-stageable die attach adhesives
View Patent ↗The present invention relates to b-stageable die attach adhesives, methods of preparing such adhesives, methods of applying such adhesives to the die and other substrate surfaces, and assemblies prepared therewith for connecting microelectronic circuitry.
1. A method for adhesively attaching a first substrate to a second substrate, said method comprising:
a. applying a composition to one or both of said first substrate or said second substrate, wherein the composition is a b-stage curable composition comprising:
a. a solid component heat curable at a first temperature;
b. a liquid component, which is either heat curable at a second temperature or curable upon exposure to radiation in the electromagnetic spectrum; and
c. a heat cure catalyst for the solid curable component;
b. exposing the composition-applied substrate to conditions favorable to effect cure of the liquid curable component thereof, thereby forming a b-staged curable film;
c. exposing the b-staged curable film of b. to a temperature in the range of 90° C. and 160° C. sufficient to melt the solid curable component thereof;
d. adjoining said first substrate with said second substrate to form an assembly wherein said first substrate and said second substrate are separated by the composition applied in a.; and
e. exposing the curable film of c. to a temperature condition in the range of 150° C. and 200° C. to cure the melted, solid curable component.
2. The method of claim 1 , wherein said first substrate is a chip die.
3. The method of claim 1 , wherein said first substrate and said second substrate are chip die.
4. The method of claim 1 , wherein said first substrate is a circuit board.
5. The method of claim 1 , wherein said first substrate is a circuit board without solder mask.
6. The method of claim 1 , wherein said first substrate is a circuit board with solder mask.
7. An article of manufacture comprising a semiconductor chip which is provided for attachment to and electrical interconnection with another semiconductor chip or a carrier substrate, the semiconductor chip having a first surface and a second surface, with the first surface having electrical contacts arranged in a predetermined pattern thereon for providing electrical engagement with the another semiconductor chip or the carrier substrate, respectively, and with the second surface having a b stage heat curable composition disposed on a layer or a portion thereof, wherein the composition is a b-stage curable composition comprising:
a. a solid component heat curable at a first temperature;
b. a liquid component, which is either heat curable at a second temperature or curable upon exposure to radiation in the electromagnetic spectrum; and
c. a heat cure catalyst for the solid curable component.